Generating Semantic Game Mutants

Purpose

Measure what a test suite or an agent workflow actually catches, by planting defects whose ground truth you hold. Without planted defects, a suite's detection rate is unknown: green means "no defect was found", which is indistinguishable from "no defect was looked for".

The defects here are semantic and game-specific — a scoring guard removed, an identity reused across a pool boundary, a field dropped from a save. Generic syntactic mutation (flip < to <=, delete a statement) mostly produces crashes and dead code, which any suite catches, inflating the score without measuring anything about gameplay.

What This Measures — Pick One Before Starting

These are different experiments with different setups. Running one and reporting another is the main way this instrument produces a wrong number.